Electronic systems typically use switches to route signals. A common type of switching device includes a micro-electromechanical (MEM) switch. Generally, MEM switches include a conductive beam that is coupled to one signal line, while being electrically and mechanically isolated from another signal line. When deflected downward, the conductive beam is capable of coming into mechanical and electrical contact with the other signal line, thus providing an electrical signal path between the two signal lines. Typically, electrostatic actuation is used to deflect the conductive beam. A first electrostatic plate is formed on the conductive beam and a second electrostatic plate is formed below the conductive beam. A voltage is applied to the second electrostatic plate, causing the first electrostatic plate, and thus the conductive beam, to be pulled downward. Electrostatically activated switches, however, typically require a high actuation voltage (for example, greater than about 50 V). Electrostatically activated switches may also suffer from actuation-induced non-linearity in their switch response.
Piezoelectric transducers, in general, convert electrical signals into mechanical vibrations or vice versa. Piezoelectric transducers typically utilize a piezoelectric film where electrical signals or mechanical vibrations induce a morphological change of the piezoelectric film (i.e., due to voltage application or due to a pressure applied to piezoelectric film). Piezoelectric transducers are generally used to actuate/sense different frequencies. Piezoelectric transducers may function as a resonator to provide a maximum response when operated at its resonance frequency.
One typical piezoelectric transducer includes a surface acoustic wave (SAW) transducer that, when excited, produces mechanical vibrations along the surface of the piezoelectric film. SAW piezoelectric transducers typically do not scale well to radio frequency (RF) applications due to a need for submicrometer lithography and decreasing power handling capabilities. Another type of piezoelectric transducer includes a contour-mode (CM) piezoelectric transducer that, when excited, produces mechanical vibrations throughout the piezoelectric film and where the fundamental frequency is defined by the in-plane dimensions of the piezoelectric film.